The prior art includes many night vision imaging devices that enhance or enable a person to view objects at night or in other low light conditions. A night vision imaging device typically consists of an image intensifier tube and various electronic components which are used to control the image produced by the device. Many of these night vision imaging devices are stand-alone units with objective lens assemblies for receiving images and ocular lens assemblies through which a person can directly view light-intensified images. The objective lens assemblies of such night vision imaging devices are configured to be focusable and/or are provided with a focusable ocular lens assembly, so that a person can adjust the device to meet his/her needs. Furthermore, it is very common for such night vision imaging devices to be provided with some degree of magnification power.
There are many applications, such as night time photography and night time surveillance, where it is desirable to provide a camera device such as a television camera or the like, with night vision imaging capabilities. One method of accomplishing this is to couple a night vision imaging device to the camera device just in front of the camera's objective lens assembly via a filter screw mount provided on either the body of the camera device or on the objective lens assembly itself. This requires that the objective lens assembly of the camera device be focussed on the output of the night vision device, consequently, the camera must rely solely on the optics of the night vision device for focussing and zooming.
Another method of providing a camera device with night vision imaging capabilities involves camera devices with removable objective lens assemblies, wherein the objective lens assembly is removed and the night vision imaging device is coupled directly to the lens mount provided in the body of the camera device. Again like in the previous method, the camera device must rely solely on the optics of the night vision device for focussing and zooming.
Another problem common to both methods concerns the weight of the night vision imaging device. Each night vision imaging device described above typically includes an image intensifier tube, an objective lens assembly, a focussing lens assembly, a battery source and a power supply control unit which includes means for converting an input voltage received from the battery source into a set of voltages required to power various stages of the image intensifier tube. Such night vision imaging devices add considerably to the overall weight and length of the camera device which makes it less desirable to use and operate, especially since the additional weight and length is all concentrated at the far end of the camera device. The weight of the night vision imaging device is also a factor in the longevity of the threaded mounts to which the night vision device is attached to. These lens and filter mounts have thread configurations which tend to be rather delicate. Thus, achieving a substantial reduction in the weight of the night vision device by eliminating the battery source can yield significant increases in the longevity of the threaded mounts and ease of operability of the camera device.
One solution to the weight problem described above, is to eliminate the night vision device's battery source and obtain power from a remote source such as a television camera to which the night vision device is attached. Many television camera have externally-located power jacks which enable the camera to supply power to auxiliary electronic components such as lights. Thus, it would seem that by coupling the power supply control unit of the night vision device to the power jack of the camera, the night vision device could be properly operated. However, the voltage and current generally available from these external power jacks are not directly usable by the image intensifier tube of the night vision device without making modifications to the power supply control unit. Moreover, the voltage and current available from these external power jacks vary from camera device to camera device, depending upon what type of auxiliary device the jacks were originally intended to provide power for.
A need therefore, exists for an improved universal night vision imaging device for different types of camera devices, which enables the camera devices to rely on their own optics for focusing and zooming. There is a further need for a night vision device having a substantially reduced weight and length when compared to similar prior art night vision devices, which can be powered by the externally-located power jacks of various types of camera devices.